Somewhere on the trek Tuesday out of Guadalajara, the migrant caravan heading toward the U.S. border passed the halfway point.

When the main part of the group reached the south end of Sinaloa state that evening, it had covered about 1,725 miles since leaving Honduras a month earlier. Ahead of them lay 1,425 miles to the border crossing at Tijuana.

The caravan from Central America, estimated at 5,000 people, has become more fractured as it has made its way through Mexico. While many migrants reached the Sinaloan town of La Concha on Tuesday night, some were 80 miles ahead, in Mazatlan — and a group of several hundred who arrived in Tijuana said they had been part of the original caravan.

The Tijuana city government said Tuesday that about 350 migrants had arrived and would be directed to shelters around the city.

The U.S. government said it was starting work Tuesday to “harden” the border crossing at Tijuana to prepare for the arrival of the caravan leapfrogging its way across western Mexico.

In its first days after leaving San Pedro de Sula, Honduras, on Oct. 13, the migrants covered about 30 miles a day, mostly on foot. Since reaching Mexico, they’ve been able to pick up more rides on buses and trucks, and so have covered 150 to 200 miles some days.

Small groups have broken off along the way. In addition to the hundreds reaching Tijuana, migrants from the caravan have been reported near Monterrey, 100 miles from the crossing at Laredo, Texas.

Early Tuesday, thousands from the main part of the caravan left shelters in Guadalajara and were taken by bus to a highway toll plaza to wait for rides farther north. But no other buses showed up and few trucks stopped to pick them up, leaving many to walk the 60 miles through the state of Nayarit.

The Rev. Miguel Angel Soto, director of the Casa de Migrante en Culiacan, said the Sinaloa government and the Roman Catholic Church were helping the migrants. The priest said the church had been able to get “good people” to provide buses, 24 of which had left Sinaloa on Tuesday for the eight-drive to Navojoa in Sonora state.

About 1,300 migrants in a second caravan arrived Tuesday in Mexico City, where they had their first day of rest in weeks.

— The Associated Press contributed to this article

A Catholic nun speaks to Central American migrants riding in the bed of a semi-trailer, as they move toward the U.S. border, in Ixtlán del Rio, Nayarit, Mexico, Tuesday, Nov. 13, 2018. (AP Photo/Marco Ugarte)

Central American migrants -mostly Hondurans - wait for buses at La Concha in the state of Sinaloa, Mexico on November 13, 2018. (Photo by ALFREDO ESTRELLA / AFP)

Migrants near the U.S. border in Playas de Tijuana, Mexico, on November 13, 2018. -

Central American migrants cross a street in Tijuana, Mexico, on November 13, 2018. (Photo by Guillermo Arias / AFP)

Central American migrants, part of the caravan hoping to reach the U.S. border, rest at the Benito Juarez Auditorium that is being used as a migrant shelter, in Guadalajara, Mexico, Monday, Nov. 12, 2018. . (AP Photo/Rodrigo Abd)

Migrants from poor Central American countries -mostly Hondurans- walk along the road between Zapopan and Tequila in the Mexican state of Jalisco, on their trek north, on November 13, 2018. (Photo by ULISES RUIZ / AFP)

Migrants at a tollbooth on the road between Zapopan and Tequila in the Mexican state of Jalisco, on their trek north, on November 13, 2018. - (Photo by ULISES RUIZ / AFP)

Migrants walk along the road between Zapopan and Tequila in the Mexican state of Jalisco, on their trek north, on November 13, 2018. (Photo by ULISES RUIZ / AFP)

On the road between Zapopan and Tequila in the Mexican state of Jalisco. (Photo by ULISES RUIZ / AFP)

US Department of Defence personnel install barriers requested by Custom and Border Protection at the San Ysidro port of entry, as seen from the Mexican side of the border in Tijuana, Mexico, on November 13, 2018. - (Photo by GUILLERMO ARIAS / AFP)

Central American migrants, part of the caravan hoping to reach the U.S. border, get a ride in a truck, in Irapuato, Mexico, Monday, Nov. 12, 2018. (AP Photo/Marco Ugarte)

Central American migrant head to a shelter on the outskirts of Zapotlanejo, Jalisco state, Mexico on November 11, 2018. - (Photo by Ulises Ruiz / AFP)

Central American migrants -mostly Honduran- tget on board a truck heading to Irapuato in the state of Guanajuato on November 11, 2018 after spending the night in Queretaro. (Photo by ALFREDO ESTRELLA / AFP)

Police officers stand guard as Central American migrants wait to be taken to a shelter, in the outskirts of Zapotlanejo, Jalisco state, Mexico on November 11, 2018. (Photo by Ulises Ruiz / AFP)

Central American migrants moving in a caravan towards the United States, descend from a truck to be taken to a shelter, in the outskirts of Zapotlanejo, Jalisco state, Mexico on November 11, 2018. - (Photo by Ulises Ruiz / AFP)

Central American countries board buses to head to a shelter in Zapotlanejo, Jalisco state, Mexico. (Photo by Ulises Ruiz / AFP)ULISES RUIZ/AFP/Getty Images

A couple of Central American migrant girls, part of the caravan hoping to reach the U.S. border, get a ride in a chicken truck, in Irapuato, Mexico, Monday, Nov. 12, 2018. (AP Photo/Rodrigo Abd)

A man taking part in a caravan of migrants from poor Central American countries gets a ride on a tanker truck on the Irapuato-Guadalajara highway. (Photo by Alfredo ESTRELLA / AFP)

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